It is known to use high tenacity fibers such as polyaramid fibers in multilayer structures to provide ballistic protection in body armor. Bullet resistant vests of multilayer structure have proven very satisfactory as body armor for men and women, but difficulties have been encountered in improving comfort for female wearers by shaping the armor to adapt to the female body.
Wearer comfort and the effectiveness of the armor to prevent injury are closely related. Depending on the protection level and the fabric type, about 10 to 50 layers of fabric are used. This produces a somewhat stiff structure that does not readily adapt to pronounced body contours, particularly over the female breast region. If the armor does not lie in snug contact with the wearer's body, shock transmission becomes uneven and the body armor does not perform as it should. The body armor's shaped areas are particularly liable to damage by shots at a glancing angle of incidence. Moreover, female breasts are specially liable to traumatic shock injury.
Various proposals for multilayer body armor specially shaped to protect shaped areas of the body such as women's breasts have already been made. But making multilayer armor in special shapes is rendered difficult due to the fact that the layers of penetration resistant material are flexible but relatively inelastic. Problems have therefore been encountered.
Contouring a front armor panel by joining cut panels of the fabric with overlapping seams using a special stitching pattern was proposed in U.S. Pat. No. 4,183,097. However, if the overlapping seams are not large enough, angle shots can penetrate the vest, whereas increasing the size of the overlapping seams creates a hard rim in a region where women need as much flexibility as possible.
U.S. Pat. No. 4,578,821 proposed inserting a flexible multilayer ballistic panel into a front pocket of a carrier garment. This panel is held by a VELCRO hook-and-pile fastener enabling adjustment to different bust sizes, but the protected area is limited and the VELCRO fastener cannot ensure good ballistic performance. This system is hence suitable for low protection levels only.
U.K. Patent Specification 2,231,481 proposed a vest whose inner part has a foamed plastic material shaped to fit the breast. A shaped stiff or semi-stiff shock-absorbing sheet is added to the plastic layers and finally a multilayer ballistic pack is inserted, the entire arrangement being enclosed in a bag. With this design, the ballistic pack adapts to the shape by folding about a horizontal line. This can only be achieved by leaving large openings at the left and right sides of the chest, so protection in these side areas will be questionable. Moreover, the vest will be relatively heavy, stiff and uncomfortable to wear.
Another proposal made in U.S. Pat. No. 5,020,157 was the use of rigid, inflexible cups made of high strength laminated polyethylene material which are worn over a woman's breast and under a conventional soft body vest to protect from injuries resulting from ballistic impact. The impact-generated pressure will nevertheless be transmitted to the cup's rim which could cause injury. In addition, the stiff cups will be uncomfortable to wear.
Shaping body armor by molding layers of aramid fabric in a PVC shell with the aid of pressure at 400-800 kPa and heat at 180-300.degree. C. has been proposed in DE-A4423194 and in WO 96/01405. However aramid fibers have an elongation up to 4% which can lead to damage in molding. Moreover, shaping the layers stretches the fabric which would increase the gaps between the fibers and reduce ballistic efficiency. Also, this molding in a PVC shell makes the armor relatively stiff.
The above-discussed prior proposals for specially shaped multilayer body armor have therefore failed to produce a lightweight multilayer structure which fits to the body comfortably while providing excellent ballistic protection and which can be manufactured using available equipment operating at ambient temperature, or using simple thermal bonding techniques.